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From Wukang Lin <vboylin1...@gmail.com>
Subject Some questions on HLog
Date Thu, 24 Oct 2013 15:49:57 GMT
Hi all,
    Recently, i read the source of HBase's HLog, and i got some questions
that puzzled me a lot. here there are:
    1 why use reflection to init a SequenceFile.Writer
in SequenceFileLogWriter? i read HBASE-2312 but still can't catch the point.
     2 It seems that hlog use SequenceFile.Writer's append method to sync
the WAL logs to DataNode, not FSDataOutputStream.hflush(), for each
mutation(or batch mutations), so may it lose data when HDFS crash while WAL
logs were 'sync' to DataNode but not flush to disk? or are there something
i misunderstanded?

      Thank you.

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